US President Donald Trump holds the state flag of Texas outside of the Annaville Fire House after attending a briefing on Hurricane Harvey in Corpus Christi, Texas on August 29, 2017. JIM WATSON, AFP/Getty Images

John Tuan returns to rescue his dog who was left in his flooded house in the Clodine district after Hurricane Harvey caused heavy flooding in Houston, Texas on August 29, 2017. MARK RALSTON, AFP/Getty Images

Texas Army National Guard members Sergio Esquivel, left, and Ernest Barmore carry 81-year-old Ramona Bennett after she and other residents were rescued from their Pine Forest Village neighborhood due to high water from Hurricane Harvey August 29, 2017 in Houston, Texas. Erich Schlegel, Getty Images

Residents are evacuated from flooded homes following Tropical Storm Harvey in the Cypresswood Creek subdivision in north Houston on Monday, Aug. 28, 2017 in Houston. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards of 40 inches of rain over the next couple of days. Win McNamee, Getty Images

Houston resident Karen Hudson is evacuated from her home after severe flooding following Hurricane Harvey in the Cypresswood Creek subdivision in north Houston on Monday, Aug. 28, 2017. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards of 40 inches of rain over the next couple of days. Win McNamee, Getty Images

Floodwaters approach the tops of homes following Hurricane Harvey on Monday, Aug. 28, 2017 in Houston. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards to 40 inches of rain in Texas over the next couple of days. Joe Raedle, Getty Images

A family wades through water to escape their home on Highway 90 on Monday, Aug. 28, 2017, after Hurricane Harvey caused heavy flooding in Houston.
Rescue teams in boats, trucks and helicopters scrambled Monday to reach hundreds of Texans marooned on flooded streets in and around America's fourth-largest city before monster storm Harvey returns. Mark Ralston, AFP/Getty Images

People evacuate their flooded homes in the walke of Hurricane Harvey on Monday, Aug. 28, 2017 in Houston. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards to 40 inches of rain in Texas over the next couple of days. Joe Raedle, Getty Images

People are ferried from a flooded neighborhood in the wake of Hurricane Harvey, on Monday, Aug. 28, 2017 in Houston. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards to 40 inches of rain in areas of Texas over the next couple of days. Scott Olson, Getty Images

People are ferried from a flooded neighborhood in the wake of Hurricane Harvey, on Monday, Aug. 28, 2017 in Houston. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards of 40 inches of rain in areas of Texas over the next couple of days. Scott Olson, Getty Images

Flood victims wait to unload from the back of a heavy duty truck after being evacuated from their homes amid rising floodwaters in the wake of Tropical Storm Harvey on Monday, Aug. 28, 2017, in Houston. David J. Phillip, AP

Evacuees fill cots at the George Brown Convention Center, which has been turned into a shelter run by the American Red Cross to house victims of the high water from Hurricane Harvey on Monday, Aug. 28, 2017 in Houston. Erich Schlegel, Getty Images

Flood evacuee from Houston's 5th Ward, Korbey Haley, shares a light moment with his son Jordan Haley, 6, at the George Brown Convention Center. The site has been turned into a shelter run by the American Red Cross to house victims of the high water from Hurricane Harvey on Monday, Aug. 28, 2017 in Houston. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards of 40 inches of rain in areas of Texas over the next couple of days. Erich Schlegel, Getty Images

Evacuees fight the rain outside the George Brown Convention Center, which has been turned into a shelter run by the American Red Cross to house victims of the high water from Hurricane Harvey on Monday, Aug. 28, 2017 in Houston. Erich Schlegel, Getty Images

Rhonda Worthington talks on her cell phone with a 911 dispatcher while exiting her stalled vehicle amid rising floodwaters from Tropical Storm Harvey in Houston on, Monday, Aug. 28, 2017. Worthington said she thought the water was low enough to drive through before the vehicle started to float away. LM Otero, AP

Neighborhood evacuees wade down a flooded street on Monday, Aug. 28, 2017 in Houston. Tropical Storm Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards to 40 inches of rain in Texas over the next couple of days. Joe Raedle, Getty Images

Flood victims gather for food at a shelter in the George R. Brown Convention Center during the aftermath of Tropical Storm Harvey on Monday, Aug. 28, 2017 in Houston. Brendan Smialowski, AFP/Getty Images

Houston Police SWAT officer Daryl Hudeck carries Connie Pham and her 13-month-old son Aiden after rescuing them from their home surrounded by floodwaters from Tropical Storm Harvey Sunday in Houston. The remnants of Hurricane Harvey sent devastating floods pouring into the city, sending thousands scrambling to rooftops or higher ground. David J. Phillip, AP

Evacuees wade down a section of Interstate 610 amid rising floodwaters from Tropical Storm Harvey Sunday in Houston. The devastation had thousands of people scrambling to rooftops or higher ground. David J. Phillip, AP

Steve Culver cries with his dog Otis as he talks about what he said was the, "most terrifying event in his life," when Hurricane Harvey blew in and destroyed most of his home while he and his wife took shelter there on August 26, 2017 in Rockport, Texas. Joe Raedle, Getty Images

Bricks and other debris lie on the ground after damage to a home from what is believed to be a tornado touchdown in the Sienna Plantation area of Missouri City, Texxas as a result of Hurricane Harvey on Saturday, Aug. 26, 2017. Elizabeth Conley, Houston Chronicle

Dave McGrew looks into the cabin of an 18-wheeler that was flipped on its side on Highway 59 West as Hurricane Harvey hit the Central Gulf Coast Saturday, Aug. 26, 2017, in Texas. Mcgrew stopped while on his way to check on his family in Victoria, Texas. Godofredo A. Vasquez, Houston Chronicle

Tammy Rendon tries to clean up debris around her home in the Hillcrest neighborhood of Corpus Christi, Texas, on Saturday, Aug. 26, 2017. She said that when the winds were heaviest from Hurricane Harvey the glass was sucked from the frame in her home. Hillcrest is one of the poorest communities in Corpus Christi. "Where are all our friends now," she asked as she worked to help uncover the garage where her vehicle was stuck. Rachel Denny Clow, Corpus Christi Caller-Times

Mark Metzger wears a suit as he climbs over rocks as he carries his surfboard in Galveston, Texas as Hurricane Harvey intensifies in the Gulf of Mexico Friday, Aug. 25, 2017. Harvey is forecast to be a major hurricane when it makes landfall along the middle Texas coastline. David J. Phillip, AP

Larger than usual waves come ashore at Crystal Beach as Hurricane Harvey approaches Texas on Friday, Aug. 25, 2017 in Crystal Beach, Texas. Harvey intensified into a hurricane Thursday and steered for the Texas coast with the potential for up to 3 feet of rain, 125 mph winds and 12-foot storm surges in what could be the fiercest hurricane to hit the United States in almost a dozen years. Guiseppe Barranco, The Beaumont Enterprise via AP

A tree blocks a street as Hurricane Harvey makes landfall in Corpus Christi, Texas, on Friday, Aug. 25, 2017. Hurricane Harvey smashed into Texas late Friday, lashing a wide swath of the Gulf Coast with strong winds and torrential rain from the fiercest hurricane to hit the U.S. in more than a decade. Nick Wagner, Austin American-Statesman via AP

Keedan Garcia, 8, holds his kitten as he waits with his family to be evacuated as the outer bands of Hurricane Harvey begin to make landfall, Friday, Aug. 25, 2017, in Corpus Christi, Texas. Eric Gay, AP

Hillary Lebeb walks along the seawall in Galveston, Texas as Hurricane Harvey intensifies in the Gulf of Mexico Friday, Aug. 25, 2017. Harvey is forecast to be a major hurricane when it makes landfall along the middle Texas coastline. David J. Phillip, AP

Evacuees line up to apply for FEMA aid at the Convention Center which is housing people from flooded homes after Hurricane Harvey caused heavy flooding in Houston, Texas on Tuesday(Photo: MARK RALSTON / AFP/Getty Images)

Houston — With its flood defenses strained, the crippled city of Houston anxiously watched dams and levees Tuesday to see if they would hold until the rain stops, and meteorologists offered the first reason for hope — a forecast with less than an inch of rain and even a chance for sunshine.

The human toll continued to mount, both in deaths and in the ever-swelling number of scared people made homeless by the catastrophic storm that is now the heaviest tropical downpour in U.S. history.

The city’s largest shelter was overflowing when the mayor announced plans to create space for thousands of extra people by opening two and possibly three more mega-shelters.

“We are not turning anyone away. But it does mean we need to expand our capabilities and our capacity,” Mayor Sylvester Turner said. “Relief is coming.”

Louisiana’s governor offered to take in Harvey victims from Texas, and televangelist Joel Osteen opened his Houston megachurch, a 16,000-seat former arena, after critics blasted him on social media for not acting to help families displaced by the storm.

Meteorologists said the sprawling city would soon get a chance to dry out.

When Harvey returns to land Wednesday, “it’s the end of the beginning,” National Hurricane Center meteorologist Dennis Feltgen said.

Harvey will spend much of Wednesday dropping rain on Louisiana before moving on to Arkansas, Tennessee and parts of Missouri, which could also see flooding.

But Feltgen cautioned: “We’re not done with this. There’s still an awful lot of real estate and a lot of people who are going to feel the impacts of the storm.”

The National Weather Service predicted less of an inch of rain for Houston on Wednesday and only a 30 percent chance of showers and thunderstorms for Thursday. Friday’s forecast called for mostly sunny skies with a high near 94.

In all, more than 17,000 people have sought refuge in Texas shelters, and that number seemed certain to increase, the American Red Cross said.

The city’s largest shelter, the George R. Brown Convention Center, held more than 9,000 people, almost twice the number officials originally planned to house there. The crowds included many from outside Houston.

Louisiana Gov. John Bel Edwards said he expected Texas officials to decide within 48 hours whether to accept his offer, which comes as Louisiana deals with its own flooding. About 500 people were evacuated from flooded neighborhoods in southwest Louisiana, Edwards said.

The city has asked the Federal Emergency Management Agency for more supplies, including cots and food, for an additional 10,000 people, said the mayor, who hoped to get the supplies no later than Wednesday.

In an apparent response to scattered reports of looting, the mayor also imposed a curfew. Police Chief Art Acevedo said violators would be questioned, searched and arrested.

Four days after the storm ravaged the Texas coastline as a Category 4 hurricane, authorities and family members have reported more than 10 deaths from Harvey. They include a woman killed when heavy rain sent a large oak tree crashing onto her trailer and another woman who apparently drowned after her vehicle was swept off a bridge.

Houston police confirmed that a 60-year-old officer drowned in his patrol car after he became trapped in high water while driving to work. Sgt. Steve Perez had been with the force for 34 years.

Six members of a family were feared dead after their van sank into a drainage channel in East Houston. A Houston hotel said one of its employees disappeared while helping about 100 guests and workers evacuate the building.

Authorities acknowledge that fatalities from Harvey could soar once the floodwaters start to recede from one of America’s largest metropolitan centers.

A pair of 70-year-old reservoir dams that protect downtown Houston and a levee in a suburban subdivision began overflowing Tuesday, adding to the rising floodwaters.

Engineers began releasing water from the Addicks and Barker reservoirs Monday to ease the strain on the dams. But the releases were not enough to relieve the pressure after the relentless downpours, Army Corps of Engineers officials said. Both reservoirs are at record highs.

The release of the water means that more homes and streets will flood, and some homes will be inundated for up to a month, said Jeff Linder of the Harris County Flood Control District.

Brazoria County authorities posted a message on Twitter warning that the levee at Columbia Lakes south of Houston had been breached and telling people to “GET OUT NOW!!” Brazoria County Judge Matt Sebesta said residents were warned that the levee would be overtopped at some point, and a mandatory evacuation order was given Sunday.

The levee was later fortified, but officials said they did not know how long the work would hold.

Officials in Houston were also keeping an eye on infrastructure such as bridges, roads and pipelines that are in the path of the floodwaters.

Water in the Houston Ship Channel, one of the nation’s busiest waterways, which serves the Port of Houston and Houston’s petrochemical complex, is at levels never seen before, Linder said.

The San Jacinto River, which empties into the channel, has pipelines and roads and bridges not designed for the current deluge, Linder said, and the chance of infrastructure failures will increase the “longer we keep the water in place.”

Among the worries is debris coming down the river and crashing into structures and the possibility that pipelines in the riverbed will be scoured by swift currents. In 1994, a pipeline ruptured on the river near Interstate 10 and caught fire.

After five consecutive days of rain, Harvey set a new continental U.S. record for rainfall for a tropical system.

The rains in Cedar Bayou, near Mont Belvieu, Texas, totaled 51.88 inches (132 centimeters) as of Tuesday afternoon. That’s a record for both Texas and the continental United States, but it does not quite surpass the 52 inches (133 centimeters) from Tropical Cyclone Hiki in Kauai, Hawaii, in 1950, before Hawaii became a state.

The previous record was 48 inches (122 centimeters) set in 1978 in Medina, Texas, by Tropical Storm Amelia. A weather station southeast of Houston reported 49.32 inches (125 centimeters) of rain.

Before it breaks up, Harvey could creep as far east as Mississippi by Thursday, meaning New Orleans, where Hurricane Katrina unleashed its full wrath in 2005, is in Harvey’s path. Foreboding images of Harvey lit up weather radar screens on the 12th anniversary of the day Katrina made landfall in Plaquemines Parish.

The disaster is unfolding on an epic scale, with the nation’s fourth-largest city mostly paralyzed by the storm that arrived as a Category 4 hurricane and then parked over the Gulf Coast. The Houston metro area covers about 10,000 square miles (25,900 square kilometers), an area slightly bigger than New Jersey.

Associated Press writers Frank Bajak and Michael Graczyk in Houston, Diana Heidgerd and David Warren in Dallas, Seth Borenstein in Washington and Tammy Webber in Chicago contributed to this report.